We are investigating the psychobiology of cognition in man. We attempt to interrelate psychological and biological determinants of various components of cognition such as the specific and discrete psychobiological mechanisms that define the acquisition, processing, consolidation and retrieval of experience. Experiments are designed to examine the biological and psychological determinants of psychiatric and neuropsychiatric alterations in cognitive processes in adults and children. These same cognitive processes are examined under drug altered conditions. Some of these studies have examined whether drugs that enhance aspects of cognition would reverse cognitive disturbances in patients. Findings include changes in encoding, memory and retrieval that occur in response to drug treatments that alter cholinergic, noradrenergic and neuroendocrine central nervous system activity, as well as cognitive changes produced by neuropeptides, in the dementias, aging, and in depressed patients. All of the studies are designed to help define the psychobiology and determinants of cognition by continuing forms of cognitive changes that are apparent in a variety of syndromes and in response to changes in central nervous system activity.